Small kitchens: should you extend?

If your kitchen is impractically small and you have space to extend, here are some suggestions on how to do it and how much it will cost

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If your current kitchen simply doesn’t have the space you need and you have considered all of the options to remodel, it may be worth adding an extension. This is provided you have the space in the garden and that local property values justify the investment.

When is it worth extending?

  • If you can’t remodel the existing space to accommodate what you need;
  • When the value you will add to the property by extending will definitely be larger than your expenditure. Remember every location has a ceiling value though so check the sale prices of similar properties nearby;
  • If you couldn’t get the house you want – within your budget – by moving.

How much will it cost?

The quality of the materials you use – especially the kitchen units, worktops, appliances, floor finishes, sink and taps – will have the biggest influence on the final cost of your project. If you have the budget, use a builder to undertake any actual renovation work and a specialist to design and install your new kitchen.

If your budget is tight, you can cut costs by doing some of the work yourself, or by employing individual subcontractors. You could save 10-15 per cent by being your own project-manager and/or contractor, and reduce the VAT on labour, too.

Material costs are fairly consistent across the UK and off-the-shelf units offer excellent value. If you negotiate, you can get some excellent discounts out there. For flooring, kitchen units, appliances, lighting and tiles, shop around local trade suppliers, DIY sheds and online.

There are three key extension types you could consider:

A bay window

This makes a room appear larger and could incorporate a window seat, yet it requires no groundworks as it simply projects from the existing building. So it can work at first-floor level as well, if you live in a flat (subject to planning consent). A small projecting bay window could be added for about £1,600-£2,400 and is a job for a carpenter or general builder.

A conservatory or orangery

A small conservatory could be used as an extension to an existing room, providing the total glazed area is not too large, and still complies with the Building Regulations for energyefficiency. A conservatory is ideal for a dining area. Construction costs range from £800-£1,200 per m². Building one is a job for a general builder or a specialist conservatory company.

A full extension

If you need to add more space with a side or rear extension to enlarge your kitchen, expect to pay about £950-1,450 per m² using a main contractor for a standard extension, and £1,450-£2,200 per m² for a more contemporary-style specialist design.

Will you need planning permission?

Alterations to flats or any leasehold property will need consent from the freeholder. Converting existing space such as a cellar or garage can usually be undertaken without the need for a planning application, as it falls within the definition of Permitted Development.

Smaller extensions to the rear of the property will also fall under Permitted Development if they meet the following conditions:

  • Single-storey rear extensions must not extend more than six metres beyond the rear wall of an attached house, or eight metres if detached, with a maximum height of four metres
  • Your extension must not be higher than the original roof
  • Two-storey extensions must not be closer than seven metres to the rear boundary
  • The roof pitch of extensions higher than one storey should match the existing house
  • Build in the same, or similar material to the existing house
  • Extensions must not go beyond the principal or side elevation fronting a highway
  • Side extensions must be single-storey, no higher than four metres, and no wider than half of the original building
  • In designated areas, side extensions require planning permission and rear extensions must be single-storey
  • An extension must not result in more than half the garden or land being covered
  • Upper-floor, side-facing windows must be obscure-glazed, and any opening part must be 1.7m above the room’s floor
  • Extensions must not cover more than 50 per cent of the garden (and this is calculated to include outbuildings)

If in doubt, always contact your local planning department.

Building Regulations

All new building work and alterations will need to comply with the building regulations – these are minimum construction standards legally enforced to make sure homes are safe, well built, hygienic and energy-efficient. You will need to notify your local authority building control department of your proposed works and pay a fee for the inspection and subsequent approval.

Who will design and build my extension?

You can do the drawings for basic alterations yourself. For more complex changes, though, it is generally worth employing a designer such as an architect, architectural technologist, or a building surveyor. Structural alterations, such as removing walls, must be assessed by a structural engineer (find one in your local area by visiting and they will need to produce drawings and calculations to demonstrate compliance with building regs.

Renovation and remodelling work can be undertaken on a DIY basis. The only work you cannot do yourself is anything that involves gas appliances. These must, by law, be undertaken by a suitably qualified tradesman who is a member of the Gas Safe Register (for more details visit,